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Purpose: Soil moisture constitutes a pivotal component of the hydrological cycle, vital for drought forecasting and climate change studies. Despite the development of remote sensing technology offering a robust means for soil moisture content (SMC) monitoring, the exclusive use of a single data source for SMC monitoring commonly has problems with poor timeliness and low accuracy, particularly within vegetated regions. This study aims to improve the accuracy of SMC monitoring in vegetated areas through the fusion of radar and multispectral data and to explore the influence of soil depth on SMC inversion. Methods: Shahaoqu was selected as the study area, which has a variety of crop types. During the sampling period, the crops were flourishing. Fifteen spectral indices and fourteen radar feature parameters were extracted from Sentinel multispectral and radar data, respectively, with the variable importance projection (VIP) method used for variable selection. The SMC inversion model was built using three algorithms: Multiple Linear Regression (MLR), Back Propagation Neural Network (BPNN), and Support Vector Machine (SVM). Results: The SMC model, which had synergistically combined Sentinel radar and optical data, showed improved stability and inversion accuracy. It achieved a high adjusted coefficient of determination (R2) of up to 0.731 and a root mean square error (RMSE) of 2.2%. The inversion accuracy of the three algorithms at varying soil depths ranks as follows: 0–10 cm, 10–20 cm, and 0–20 cm, from best to worst. The machine learning models ranked by inversion accuracy from highest to lowest are SVM, BPNN, and MLR. Conclusions: This study presents an efficient method for fusing Sentinel optical and radar remote sensing data for soil moisture inversion. It can effectively invert soil moisture under different vegetation types, providing essential theoretical foundations for precision agriculture and environmental management.

Body-conformable light-emitting devices have generated considerable interest because of their widespread potential applications in aerospace, medicine and electronics. These devices, which are flexible, stretchable and soft, can integrate seamlessly and inconspicuously with the human body for tasks such as real-time monitoring, display of information, biosensing, optogenetic stimulation and medical therapy. At present, designs can be roughly divided into three different types: wearable light-emitting textiles, attachable light-emitting skins and implantable light-emitting biodevices. Here we evaluate recent advances in all three areas, discussing the materials design, device engineering strategies and diverse applications of these devices. The outstanding challenges and issues that need to be resolved before achieving widespread adoption and improved capabilities are highlighted.

Applying the staggered grid finite difference method (SGFDM) for simulating acoustic responses in large-scale, complex, 3-D models poses substantial challenges in geophysics, especially in high-resolution stratigraphic model, due to the high computational burden. To address this problem, we have proposed a low overhead parallel optimization method (LOPOM) suitable for heterogeneous architectures, using high-resolution borehole models as examples. The LOPOM enhances computational intensity and optimizes memory bandwidth utilization. This is achieved through the technique of data reuse along the discontinuities of the model and by minimizing such discontinuities within the halo region. LOPOM was implemented and tested on the CUDA platform and the Sunway supercomputer. In each instance, LOPOM demonstrated an optimal acceleration ratio, thus proving its robust performance. Furthermore, the method’s effectiveness was confirmed through its application to fracture-vuggy formation models and digital core models. Finally, the numerical simulation results and the actual logging data are combined to illustrate the application value of LOPOM.

Soil salinization is a vital factor in global land degradation, seriously affecting sustainable agricultural development. Efficient monitoring of soil salinity using satellite remote sensing is critical for saline soil management. Currently, research on soil salinity extraction using satellite remote sensing primarily relies on the spectral information of remote sensing images, but insufficient consideration was given to the texture features of the imagery and the integration of spectral and texture information. To fully explore the effectiveness of texture features and the integration of texture features and spectral information in soil salinity estimation, experiments were conducted in Shahaoqu Irrigation Area, Inner Monglia, China from April to August 2019. To this end, the experiments utilized measured soil salinity data and the textural and spectral data from Sentinel-1/2. The effectiveness of Sentinel-1/2 texture features in soil salinity estimation was examined using out-of-bag score, and soil salinity inversion models were constructed based on the texture features, spectral information, and four machine learning models [random forest, Cubist, support vector machines (SVMs), and backpropagation (BP)]. The results indicated that Sentinel-1 texture features were more sensible to bare soil salinity (the top four most sensible texture features were HOM, ENT, COR, and CON), while Sentinel-2 texture features were more sensible to vegetated soil salinity (the top four were VAR, CON, HOM, and ENT). In addition, when combining texture features and spectral information, the models exhibited improved performance, and random forest had the best performance in both bare soil ( ${R}^{{2}}$ = 0.688 and RMSE = 0.207) and vegetated soil ( ${R}^{{2}}$ = 0.494 and RMSE = 0.304).

To further improve the strength of an Al–Ce alloy, the effects of electromagnetic stirring treatment, Sc–Zr microalloying, and their compound action on the microstructure and properties of the Al–8Ce alloy were investigated for the first time in this study. The results show that the primary α-Al becomes coarse, the eutectic Al11Ce3phase is refined and the lamellar spacing increases significantly due to the combined effect of forced convection of electromagnetic field and dendrite fragmentation and nucleation in Al–8Ce alloy after electromagnetic stirring treatment. After the Sc–Zr microalloying treatment of the Al–8Ce alloy, the α-Al changes from a dendritic to fine round morphology, and the eutectic Al11Ce3phase changes from lamellar to fibrous, which is due to the heterogeneous nucleation of Al3(Sc, Zr) phase and the adsorption refinement caused by the enrichment of Sc and Zr. The optimization effect of Sc–Zr microalloying on the mechanical properties of the Al–8Ce alloy was better than that of electromagnetic stirring and their synergistic treatment. The tensile strength and yield strength of Al–8Ce alloy with Sc–Zr additions were increased from 157 MPa to 85 MPa–192 MPa and 115 MPa, respectively, by 22.3 % and 35.3 %. After aging treatment, the tensile strength (from 192 to 272 MPa) and yield strength (from 115 to 221 MPa) significantly improved owing to the secondary precipitation of Al3(Sc, Zr) particles. The precipitation strengthening of the Al3(Sc, Zr) phase was the main contributor to the high yield strength of the alloy.

High-quality panoramic images captured by unmanned aerial vehicle (UAV) for farmland remote sensing play a crucial role in monitoring crop growth. However, the stitching algorithms that rely on local image matching often face challenges due to high similarity in color and texture of farmland remote sensing images. In this work, for the first time, we explore the spatial arrangement reflected by these geographic coordinates of each captured image during the UAV flight to obtain the high-quality panoramic images. We theoretically propose a novel algorithm for preserving the spatial arrangement structure based on the triangular similarity transformation, which ensures that the spatial arrangement of all images in the stitched image remains invariant to that before stitching. Moreover, we incorporate the proposed spatial arrangement preservation (SAP) module as an energy term into the global similarity prior (GSP) stitching model and thus obtain the proposed SAP-GSP stitching method. In a wheat-dominated experimental field, we collected UAV remote sensing images at various flight altitudes and multiple growth stages over a three-year period, which formed the image stitching dataset (Wheat-UAV). We evaluated the proposed SAP-GSP algorithm from both subjective and objective perspectives on Wheat-UAV dataset. The experimental results conclusively demonstrate that the SAP-GSP algorithm outperforms representative stitching algorithms in terms of preserving spatial arrangement and achieving natural-looking global stitched images. The proposed SAP-GSP offers a novel and effective technique for robustly capturing large-scale UAV remote sensing panoramic images in agricultural fields.

Two-dimensional conjugated polymers (2DCPs), composed of multiple strands of linear conjugated polymers with extended in-plane π-conjugation, are emerging crystalline semiconducting polymers for organic (opto)electronics. They are represented by two-dimensional π-conjugated covalent organic frameworks, which typically suffer from poor π-conjugation and thus low charge carrier mobilities. Here we overcome this limitation by demonstrating two semiconducting phthalocyanine-based poly(benzimidazobenzophenanthroline)-ladder-type 2DCPs (2DCP-MPc, with M = Cu or Ni), which are constructed from octaaminophthalocyaninato metal(ii) and naphthalenetetracarboxylic dianhydride by polycondensation under solvothermal conditions. The 2DCP-MPcs exhibit optical bandgaps of ~1.3 eV with highly delocalized π-electrons. Density functional theory calculations unveil strongly dispersive energy bands with small electron–hole reduced effective masses of ~0.15m0for the layer-stacked 2DCP-MPcs. Terahertz spectroscopy reveals the band transport of Drude-type free carriers in 2DCP-MPcs with exceptionally high sum mobility of electrons and holes of ~970 cm2V−1s−1at room temperature, surpassing that of the reported linear conjugated polymers and 2DCPs. This work highlights the critical role of effective conjugation in enhancing the charge transport properties of 2DCPs and the great potential of high-mobility 2DCPs for future (opto)electronics.

Zeolite foamed asphalt - warm mix mixture (ZFA-WMM) has been applied in large quantities in asphalt pavement, however, a lower construction temperature, residual zeolite water and zeolite minerals have different effects on the cohesion and adhesion properties of zeolite foamed asphalt (ZFA), which indirectly affects the water stability of its mixture. This study analyzed the interface behavior in ZFA-WMM using molecular dynamics simulation. First, the molecular model of ZFA was constructed, and its thermodynamic properties were calculated and compared with experimental values and related simulated values to validated the reasonable of model. Then, the interface models of ZFA-aggregate (quartz and calcite) and ZFA-ZFA were established, simulating the effects of the zeolite mineral dosage, temperature, and interface moisture (residual zeolite water) content on the cohesion and adhesion of ZFA. Furthermore, the occurrence mode of cohesion or adhesion failures in ZFA-WMM were predicted by comparing the ZFA-aggregate adhesion work with ZFA cohesion work. The simulation results indicated that as the zeolite mineral dosage increased, the ZFA cohesion and ZFA-calcite adhesion increased, while ZFA-quartz adhesion first grew and then dropped, reaching its maximum at 9.4 % zeolite mineral dosage. Under the pavement operating temperature range (-15°C∼65°C), higher pavement temperatures are beneficial to ZFA-aggregate adhesion; the cohesion of ZFA first increases and then decrease as temperature rises, reaching its maximum at 25℃. The larger the interface moisture content, the higher the possibility of water separating ZFA from the aggregate surface and the water sensitivity of ZFA-WMM. The ZFA-WMM is prone to adhesion failure, especially at higher zeolite dosages.

Stretchable polymer semiconductors (PSCs) are essential for soft stretchable electronics. However, their environmental stability remains a longstanding concern. Here we report a surface-tethered stretchable molecular protecting layer to realize stretchable polymer electronics that are stable in direct contact with physiological fluids, containing water, ions and biofluids. This is achieved through the covalent functionalization of fluoroalkyl chains onto a stretchable PSC film surface to form densely packed nanostructures. The nanostructured fluorinated molecular protection layer (FMPL) improves the PSC operational stability over an extended period of 82 days and maintains its protection under mechanical deformation. We attribute the ability of FMPL to block water absorption and diffusion to its hydrophobicity and high fluorination surface density. The protection effect of the FMPL (~6 nm thickness) outperforms various micrometre-thick stretchable polymer encapsulants, leading to a stable PSC charge carrier mobility of ~1 cm2V−1s−1in harsh environments such as in 85–90%-humidity air for 56 days or in water or artificial sweat for 42 days (as a benchmark, the unprotected PSC mobility degraded to 10−6cm2V−1s−1in the same period). The FMPL also improved the PSC stability against photo-oxidative degradation in air. Overall, we believe that our surface tethering of the nanostructured FMPL is a promising approach to achieve highly environmentally stable and stretchable polymer electronics.

Silver catalyst has been extensively investigated for photocatalytic and electrochemical CO2reduction. However, its high activity for selective hydrogenation of CO2to methanol has not been confirmed. Here, the feasibility of the indium oxide supported silver catalyst was investigated for CO2hydrogenation to methanol by the density functional theoretical (DFT) study and then by the experimental investigation. The DFT study shows there exists an intense Ag–In2O3interaction, which causes silver to be positively charged. The positively charged Ag species changes the electronic structure of the metal, facilitates the formation of the Ag–In2O3interfacial site for activation and dissociation of carbon dioxide. The promoted CO2dissociation leads to the enhanced methanol synthesis via the CO hydrogenation route as CO2∗→CO∗→HCO∗→H2CO∗→H3CO∗→H3COH∗. The Ag/In2O3catalyst was then prepared using the deposition-precipitation method. The experimental study confirms the theoretical prediction. The methanol selectivity of CO2hydrogenation on Ag/In2O3reaches 100.0% at reaction temperature of 200 °C. It remains more than 70.0% between 200 and 275 °C. At 300 °C and 5 MPa, the methanol selectivity still keeps 58.2% with a CO2conversion of 13.6% and a space-time yield (STY) of methanol of 0.453 gmethanolgcat−1h−1, which is the highest methanol STY ever reported for silver catalyst. The catalyst characterization confirms the intense Ag–In2O3interaction as well, which causes high Ag dispersion, increases and stabilizes the oxygen vacancies and creates the active Ag–In2O3interfacial site for the enhanced CO2hydrogenation to methanol.

Next-generation light-emitting displays on skin should be soft, stretchable and bright1–7. Previously reported stretchable light-emitting devices were mostly based on inorganic nanomaterials, such as light-emitting capacitors, quantum dots or perovskites6–11. They either require high operating voltage or have limited stretchability and brightness, resolution or robustness under strain. On the other hand, intrinsically stretchable polymer materials hold the promise of good strain tolerance12,13. However, realizing high brightness remains a grand challenge for intrinsically stretchable light-emitting diodes. Here we report a material design strategy and fabrication processes to achieve stretchable all-polymer-based light-emitting diodes with high brightness (about 7,450 candela per square metre), current efficiency (about 5.3 candela per ampere) and stretchability (about 100 per cent strain). We fabricate stretchable all-polymer light-emitting diodes coloured red, green and blue, achieving both on-skin wireless powering and real-time displaying of pulse signals. This work signifies a considerable advancement towards high-performance stretchable displays.

The interaction between nickel and indium oxide, together with interfacial oxygen vacancy synergistically promotes the CO2hydrogenation to methanol via the RWGS pathway where CO is the key intermediate.

Skin-like intrinsically stretchable soft electronic devices are essential to realize next-generation remote and preventative medicine for advanced personal healthcare1–4. The recent development of intrinsically stretchable conductors and semiconductors has enabled highly mechanically robust and skin-conformable electronic circuits or optoelectronic devices2,5–10. However, their operating frequencies have been limited to less than 100 hertz, which is much lower than that required for many applications. Here we report intrinsically stretchable diodes—based on stretchable organic and nanomaterials—capable of operating at a frequency as high as 13.56 megahertz. This operating frequency is high enough for the wireless operation of soft sensors and electrochromic display pixels using radiofrequency identification in which the base-carrier frequency is 6.78 megahertz or 13.56 megahertz. This was achieved through a combination of rational material design and device engineering. Specifically, we developed a stretchable anode, cathode, semiconductor and current collector that can satisfy the strict requirements for high-frequency operation. Finally, we show the operational feasibility of our diode by integrating it with a stretchable sensor, electrochromic display pixel and antenna to realize a stretchable wireless tag. This work is an important step towards enabling enhanced functionalities and capabilities for skin-like wearable electronics.

In this paper, we study the nonlinear Klein–Gordon systems arising from relativistic physics and quantum field theories

Congenital disorders of glycosylation (CDG) are a group of genetic, mostly multisystem disorders, which often involve the central nervous system. ALG3-CDG is one the some 130 known CDG. Here we report two siblings with a severe phenotype and intrauterine death. Whole-exome sequencing revealed two novel variants in ALG3: NM_005787.6:c.512G>T (p.Arg171Leu) inherited from the mother and NM_005787.6:c.511C>T (p.Arg171Trp) inherited from the father.

Noise-sideband-free and narrow-linewidth photonic microwave generation based on an optical heterodyne technique is demonstrated experimentally. By beating a self-injection-locking low-noise single-frequency fiber laser and a Brillouin fiber laser, a 9.4 GHz microwave is produced, and its noise sidebands are completely suppressed. Additionally, the signal-to-noise ratio of the microwave signal is improved by 15 dB from 40 to 55 dB, and the linewidth is compressed from 1.6 to 0.53 kHz. The high-performance photonic microwave based on low-noise fiber lasers is a promising candidate in further applications such as wireless network, lidar, and satellite communication.

We study a Schrödinger system of four equations with linear coupling functions and nonlinear couplings, including the case that the corresponding elliptic operators are indefinite.For any given nonlinear coupling β>0{\beta>0}, we first use minimizing sequences on a normalized set to obtain a minimizer, which implies the existence of positive solutions for some linear coupling constants μβ,νβ{\mu_{\beta},\nu_{\beta}}by Lagrange multiplier rules.Then, as β→∞{\beta\to\infty}, we prove that the limit configurations to the competing system are segregated in two groups, develop a variant of Almgren’s monotonicity formula to reveal the Lipschitz continuity of the limit profiles and establish a kind of local Pohozaev identity to obtain the extremality conditions.Finally, we study the relation between the limit profiles and the optimal partition for principal eigenvalue of the elliptic system and obtain an optimal partition for principal eigenvalues of elliptic systems.

We study the equation wtt+ ΔSN− 1 w− μwt− δw+ h(t, ω)wp= 0, (t, ω) ∈ ℝ × SN−1, and under some conditions we prove a monotonicity theorem for its positive solutions. Applying this monotonicity theorem, we obtain a Liouville-type theorem for some nonlinear elliptic weighted singular equations. Moreover, we obtain the necessary and sufficient condition for −div(|x|θΔu) = |x|lup, x∈ ℝN{0} having positive solutions which are bounded near 0, which is also a positive answer to Souplet’s conjecture (see Phan and Souplet (2012)) on the weighted Lane-Emden equation −Δu= |x|aup, x∈ ℝN.

To ensure public health and environmental safety while adhering to the ALARA (As Low As Reasonably Achievable) principle for radiation protection, this paper presents a method for optimizing meteorological strategies for airborne radioactive emissions using the NSGA-II algorithm. The proposed method considers the individual dose, regional collective dose, and population dose around the nuclear facility. By constructing a multi-objective optimization model and integrating it with the Gaussian diffusion model and radiation dose assessment model, this approach identifies the optimal set of emission meteorological strategies to minimize both individual effective dose and collective dose within the evaluation area. Using a pressurized water reactor (PWR) nuclear power plant and the surrounding population distribution data as a case study, simulations and solutions are provided. The results demonstrate that the optimized meteorological emission strategy can significantly reduce both individual and collective dose.

Climate change poses significant challenges to the durability and performance of asphalt pavements. This study presents a comprehensive analysis of climatic factors in Ningxia, China, to establish a robust climate zoning framework for asphalt pavements. Utilizing machine learning techniques, specifically the Fuzzy C-means (FCM) algorithm, three distinct climate zones within Ningxia were divided considering climatic features such as maximum temperature, minimum temperature, average temperature, maximum temperature difference, cumulative precipitation, and cumulative radiation. Based on the historical climate data and LTPP model, five asphalt PG zones were classified in Ningxia Province. Besides, six climate sub-zones, which integrated the asphalt PG zones into climate zones, provided a more refined strategy for the asphalt selection. The study also projected future climate scenarios using the NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP-CMIP6) dataset to assess the impact of climate change on asphalt selection in Ningxia. The significant changes in pavement temperature indicated the necessity to adapt asphalt pavement designs to future climate scenarios. Overall, this research contributed to the construction of more climate-resilient pavement infrastructures and provided an analysis framework for other regions facing similar climate-induced challenges.

Mordenite with the isolated zinc ions enhanced the catalytic performance for carbonylation of dimethyl ether to methyl acetate. The addition of Zn affected the acid properties of the catalysts, further changed the rate of coke deposition.

As a novel energy-harvesting device, a triboelectric nanogenerator (TENG) can harvest almost all mechanical energy and transform it into electrical energy, but its output is low. Although the micro-nano structures of triboelectrode surfaces can improve their output efficiency, they lead to high costs and are not suitable for large-scale applications. To address this problem, we developed a novel TENG coating with charge-storage properties. In this study, we modified an acrylic resin, a friction material, with nano-BaTiO3particles and gas phase fluorination. The charge-trapping ability of nanoparticles was used to improve the output of TENG. The short-circuit current and the output voltage of coating-based TENGs featuring charge storage and electrification reached 15 µA and 800 V, respectively, without decay for longtime working. On this basis, self-powered anticorrosion and antifouling systems are designed to reduce the open circuit potential of A3 steel by 510 mV and reduce the adhesion rate of algae on the surface of metal materials. This study presents a high-output, stable, coating-based TENG with potential in practical applications for anticorrosion and antifouling.

A 10 kW peak power, 10 ns duration and 6 kHz repetition rate fiber laser system at 1553 nm based on an Er/Yb co-doped large-mode-area fiber, is demonstrated experimentally. The seed laser is provided by a DFB laser switched with a semiconductor optical amplifier. Its optical spectrum, linewidth, and beam quality are measured and discussed. This pulsed laser with short pulse duration and high peak power could be a candidate for the laser source of time-of-flight light detection and ranging (LIDAR).

Soil salinization and water scarcity are main restrictive factors for irrigated agriculture development in arid regions. Knowing dynamics of soil water and salt content is an important antecedent in remediating salinized soils and optimizing irrigation management. Previous studies mostly used remote sensing technologies to individually monitor water or salt content dynamics in agricultural areas. Their ability to asses different levels of crop water and salt management has been less explored. Therefore, how to extract effective diagnostic features from remote sensing images derived spectral information is crucial for accurately estimating soil water and salt content. In this study, Linear spectral unmixing method (LSU) was used to obtain the contribution of soil water and salt to each band spectrum (abundance), and endmember spectra from Sentinel-2 images. Calculating spectral indices and selecting optimal spectal combination were individually based on soil water and salt endmember spectra. The estimation models were constructed using six machine learning algorithms: BP Neural Network (BPNN), Support Vector Regression (SVR), Partial Least Squares Regression (PLSR), Random Forest Regression (RFR), Gradient Boost Regression Tree (GBRT), and eXtreme Gradient Boosting tree (XGBoost). The results showed that the spectral indices calculated from endmember spectra were able to effectively characterize the response of crop spectral properties to soil water and salt, which circumvent spectral ambiguity induced by water-salt mixing. NDRE spectral index was a reliable indicator for estimating water and salt content, with determination coefficients (R2) being 0.55 and 0.57, respectively. Compared to other models, LSU-XGBoost model achieved the best performance. This model properly reflected the process of soil water-salt dynamics in farmland during crop growth period. This study provided new methods and ideas for soil water-salt estimation in dry irrigated agricultural areas, and provided decision support for governance of salinized land and optimal management of irrigation.

Rare-earth (RE)-based honeycomb-lattice materials with strong spin–orbit coupled Jeff= 1/2 moments have attracted great interest as a platform to realize the Kitaev quantum spin liquid (QSL) state. Herein, we report the discovery of a family of RE-based honeycomb-lattice magnets Ba9RE2(SiO4)6(RE = Ho–Yb), which crystallize into the rhombohedral structure with the space group R3̅. In these serial compounds, magnetic RE3+ions are arranged on a perfect honeycomb lattice within the ab-plane and stacked in the “ABCABC”-type fashion along the c-axis. All synthesized Ba9RE2(SiO4)6(RE = Ho–Yb) polycrystals exhibit the dominant antiferromagnetic interaction and absence of magnetic order down to 2 K. In combination with the magnetization and electron spin resonance results, magnetic behaviors are discussed for the compounds with different RE ions. Moreover, the as-grown Ba9Yb2(SiO4)6single crystals show large magnetic frustration with frustration index f= θCW/TN> 8 and no long-range magnetic ordering down to 0.15 K, being a possible QSL candidate material. These series of compounds are attractive for exploring the exotic magnetic phases of Kitaev materials with 4f electrons.

Triboelectric nanogenerators (TENGs) with sliding-mode have developed rapidly in the field of energy harvesting and sensing. However, its surface wear and low electric output performance usually limit its applicability. Herein, a mixture of hexadecane with onion-like carbon (OLC) lubricant is added to the interface between polytetrafluoroethylene (PTFE) film and steel to enhance the triboelectrical and tribological performance. During dry friction, the friction pair is severely worn and the current output decreases gradually with the transfer of a large amount of PTFE debris in a short period. The introduction of hexadecane partly resolves the problems such as friction and wear with the reduction in the transfer of PTFE material. However, the current output decreases gradually during the friction process because there is still some slight material transfer in the interface. The electrical output of TENG is further enhanced with the addition of OLC, and its tribological properties are comparable or better than oil-based TENG. The short-circuit currents (Isc) of the oil-based TENG and the oil-OLC-based TENG are 1.5 times and 5 times that of the TENG in the dry friction state, respectively. Also, the coefficient of friction (COF) of oil-OLC-based TENG is reduced by about 75.3% compared with dry friction state. The oil-OLC-based lubricant reduces the transfer film formation, increases the effective contact area, and squeezes the air at the interface. Also, part of the OLC rolls between the two friction layers, forming a "micro-bearing", further reducing the generation of transfer film. This study provides a novel way to improve the output efficiency and prolong the service life of TENG.

Triboelectric Nanogenerators (TENGs) have recently gotten a lot of attention in the realm of human mobility. Wearable TENGs can currently be employed for human motion detection and energy harvesting, as is shown by recent studies. However, the majority of these TENGs are used in direct contact with the human body, posing a great challenge for TENGs materials in terms of comfort, breathability, wear resistance, and flexibility. This manuscript presents a novel form of non-contact motion monitoring sensor, which has been designed based on triboelectrification and electrostatic induction. As the designed sensor requires only copper and PTFE materials, it reduces the manufacturing costs. The sensor does not need to be in direct contact with the person to sense the person’s approach and distance. The working principle and other factors influencing the functioning of non-contact TENGs are also investigated. This sensor can effectively detect signals within two meters, with the current signal reaching a value of 57 nA at a distance of 20 cm. More crucially, the sensor’s distance resolution can be accurate up to 1 cm, which is critical for sensing the human body’s approach and distance. Based on this, a simple-to-manufacture, highly sensitive, and easy-to-use intelligent navigation sensor for blind navigation is designed, which can assist blind people in avoiding obstacles effectively. This simple, easy-to-prepare, and efficient TENG and sensing system shows up-and-coming prospects in motion sensing and hazard warning applications.

Consider the following system of double coupled Schrödinger equations arising from Bose-Einstein condensates etc., $\left\{ \begin{gathered} - \Delta u + u = \mu _1 u^3 + \beta uv^2 - \kappa v, \hfill \\ - \Delta v + v = \mu _2 v^3 + \beta u^2 v - \kappa u, \hfill \\ u \ne 0,v \ne 0,andu,v \in H^1 (\mathbb{R}^N ), \hfill \\ \end{gathered} \right. $where µ1, µ2are positive and fixed; κand βare linear and nonlinear coupling parameters respectively. We first use critical point theory and Liouville type theorem to prove some existence and nonexistence results on the positive solutions of this system. Then using the positive and non-degenerate solution to the scalar equation −Δω+ ω= ω3, ω∈ Hr1(ℝN), we construct a synchronized solution branch to prove that for βin certain range and fixed, there exist a series of bifurcations in product space ℝ × Hr1(ℝN) × Hr1(ℝN) with parameter κ.

Carbon nanotubes (CNT), core–sheath CNT/reduced graphene oxide nanoribbon (RGONR), CNT/RGO composite, and RGO fibers have been compared as counter electrodes to fabricate novel dye-sensitized solar cells. For the I–/I3–electrolyte, the core–sheath CNT/RGONR fiber shows the best catalytic activity, which in turn produces the highest energy conversion efficiency of 5.64%. In contrast, for the organic T–/T2electrolyte, the highest energy conversion efficiency has been produced from the CNT fiber counter electrode with the maximal value of 4.78%. The different electrocatalytic activities among these four carbon nanostructured fibers on the two typical electrolytes of I–/I3–and T–/T2have been carefully investigated in this work.

The direct conversion of CO2into CO and O2by dielectric barrier discharge (DBD) non-thermal plasma is effective with simple setup, easy on/off operation and flexibility to the CO2source. Herein, we demonstrated the frosted dielectric surface without and with ZrO2coating can significantly improve the conversion and energy efficiency of the plasma CO2decomposition in a DBD reactor, compared to the conventional un-frosted dielectric surface without ZrO2coating. The use of the frosted dielectric surface increases the dielectric capacitance, mean electron energy and micro-discharge channels, leading to increased CO2conversion and energy efficiency. The coating of ZrO2of a high dielectric constant further improves the discharge performances with further increased CO2conversion and energy efficiency. The highest energy efficiency of 7.7% was achieved within the tested conditions. The effect of CO2adsorption on ZrO2coating is negligible because of the low coating amount.

A new method for rapidly eliminating pathogenic microorganisms in large air space using spraying •OH radicals is presented in this paper. With a physical method of strong electric-field discharge, large numbers of •OH radicals were produced by the oxygen activated particles of O2+, O( 1D), O( 3P), etc., and the introducing reagent HO2−. The gram-positive bacteria Bacillus subtilis, the gram-negative bacteria Serratia marcescens, and Bacillusspores were used for the eliminating experiments. Results show that the different microorganisms were rapidly killed by •OH radicals with a concentration of 0.8 mg/L and spraying density of 21 μL/m2within 4 sec. Cell morphological changes were also observed under microscope. The cells of B. subtilisand Bacillusspores in their cellular wall, cellular membrane, or cell protoplasm were greatly destroyed when being exposed to a killing dosage of •OH radicals.Implications:Increasing air spread of pathogenic microorganisms has prompted serious concerns for their threat to environmental safety. However, there is no an effective method to rapidly eliminate these harmful microorganisms in large air space. In comparison with conventional disinfectants, advanced oxidation technology (AOT) based on hydroxyl radicals (•OH) has excellent advantages. The main problem of how to produce the •OH radicals with high concentration and large production is solved by a physical method of strong electric-field discharge. A new method for rapidly eliminating pathogenic microorganisms in large air space using spraying •OH radicals is described in this paper.

Abstract: In this paper, we establish the product formula for the fixed point index on product cone, and then, as applications, consider the existence, nonexistence and multiplicity of positive solutions for a second-order ordinary differential system with parameters. The discussion is based on the product formula and the fundamental properties of the fixed point index.

In this paper, four kinds of discharge at high pressure (≥105Pa) were discussed. The removal of SO2from simulated flue gases was experimentally investigated using a DBD (dielectric barrier discharge) micro-gap discharge. Hydroxyl (OH·) radicals of high concentration was produced using the ionization of O2and H2O to further the conversion of SO2into H2SO4in the absence of any catalyst or absorbent. With the test and analysis, a number of H2SO4droplets were captured using a semi-dry electrostatic precipitator (ESP). Therefore, a new gas-phase oxidation method for the removal of SO2without NH3additive is found.

AbstractThe conversion of methane to liquid products, hydrogen (H2), and ammonia (NH3) was investigated experimentally using microgap discharge plasma at an environmentally friendly condition. The experimental results indicated that H2and NH3were detected as the main gas products. The highest yield and production rate of H2was 14.4% (v/v) and 2974.6 μmol/min, respectively, whereas the highest yield and production rate of NH3was 8000 ppm (v/v) and 165.1 μmol/min, respectively. Particularly, the liquid products were collected on the plate and consisted of pyrrole, 2-methyl-1,4-pentadiene, α-amidopyri-dine, 2,5-dimethylpyrrole, methylpyrazine, 1-hexyne, 1,4-heptadiene, and polycyclic organic compounds. Some liquid products were the intermediates of drug, flavor, dye, and organic synthesis, as well as edible flavor. The collection efficiency in mass and energy efficiency were 26.3% at once and 22.9 g/kWh, respectively. The whole reaction process was considered to be in line with green chemistry principles.

AbstractThe removal of sulfur dioxide (SO2) from simulated flue gases streams (N2/O2/H2O/SO2) was experimentally investigated using microgap discharge. In the experiment, the thinner dielectric layers of aluminum oxide (Al2O3) were used to form the microgap discharge. With this physical method, a high concentration of hydroxyl (OH·) radicals were produced using the ionization of O2and H2O to further the conversion of SO2into sulfuric acid (H2SO4) at 120° C in the absence of any catalysts and absorbents, which were captured with the electrostatic precipitator (ESP). As a result, the increase of discharge power and concentrations of O2and H2O increased the production of OH· radicals resulting in enhanced removal of SO2from gas streams. With the test and analysis, a number of H2SO4droplets were produced in experiment. Therefore, a new method for removal of SO2in semidry method without ammonia (NH3) additive was found.

The key problem for the removal of SO2by electrical discharge methods is how to obtain the hydroxyl radicals at high concentration and large production rates. With the micro-gap discharge method, O2and H2O in simulated gas streams (N2/O2/H2O/SO2) are ionized into a large number of OH.radicals to oxidize SO2into SO3which reacts with H2O forming H2SO4droplets at 120 °C in the absence of any catalyst or absorbent. The droplets are captured with an electrostatic precipitator. As a result, conversion of SO2to primarily H2SO4is limited by the generation of OH.radicals. By increasing the reduced field and concentrations of O2and H2O, the amount of OH.radicals increase resulting in more removal of SO2from gas streams. The removal efficiency of SO2reaches 100% when the residence time is only 0.74 s. Therefore, a new gas-phase oxidation method for removal of SO2without NH3additive is found.The key problem for the removal of SO2by electrical discharge methods is how to obtain the hydroxyl radicals at high concentration and large production rates. With the micro-gap discharge method, O2and H2O in simulated gas streams (N2/O2/H2O/SO2) are ionized into a large number of OH.radicals to oxidize SO2into SO3which reacts with H2O forming H2SO4droplets at 120 °C in the absence of any catalyst or absorbent. The droplets are captured with an electrostatic precipitator. As a result, conversion of SO2to primarily H2SO4is limited by the generation of OH.radicals. By increasing the reduced field and concentrations of O2and H2O, the amount of OH.radicals increase resulting in more removal of SO2from gas streams. The removal efficiency of SO2reaches 100% when the residence time is only 0.74 s. Therefore, a new gas-phase oxidation method for removal of SO2without NH3additive is found.

We obtain multiple positive solutions of singular-Laplacian problems using variational methods. The techniques are applicable to other types of singular problems as well.

A Pilot-scale experiment for the treatment of red tide in the enclosure was done in sea area of Shandong Province, P.R. China on Aug. 25, 2002. With the method of micro-gap discharge, O2 in air and H2O in seawater are ionized and dissociated into large numbers of OH• radicals, and then dissolved into a part of seawater to form OH• solution of high concentration. With OH• concentration of 0.68 mg/L, the kill efficiencies of 29 kinds of red tide organisms such as Chaetoceros lorenzianus and so on reached 99.89%, in which bacterium and vibrio were reduced below the detection limit, also Gonyaulax cysts and Prei. Cysts with the crust were done the lowest limit of test. At the same time, the content of chlorophyll-a was decreased below the detection limit. DO (dissolved oxygen) saturation of seawater was greatly increased to 100% because the residual OH• radical was decomposed into H2O and O2 after 20 min. Therefore the treatment of red tide using OH• radicals is a kind of advanced oxidation technology, which realizes zero pollution, zero emission and zero residual in the process of the production of OH• radicals and the treatment of red tide.

Abstract A pilot-scale experiment of 20t/h for the treatment of ship’s ballast water was done in this paper. With the method of strong ionization discharge of dielectric barrier, O 2 in air and H 2 O at gas state are ionized and dissociated into large numbers of OH • radicals, and then dissolved into a part of ballast water to form dissolved OH • with the concentration of 24.3 mg/L. When the dissolved OH • concentration is 0.63 mg/L, the kill efficiencies of bacteria, mono-algae, protozoan reached 100% within 2.67 s. The contents of chl-a, chl-b, chl-c and carotenoid were decreased to 35–64% within 8.0 s and not be tested after 5 min. At the same time, the ballast water quality was greatly improved. Therefore, the treatment of ship’s ballast water using OH • radicals is a kind of advanced oxidation technology, which is considered as zero pollution, zero emission and zero residual in the process of the production, of OH • radicals and the treatment of ballast water.

A pilot-scale system of 20 t/h for the treatment of ship’s ballast water and the setup of dissolved hydroxyl radical was introduced in this paper. With this experimental system, the kill efficiencies of bacteria, mono-algae, protozoan reach 100% within 2.67 s when dissolved OH· concentration is 0.6 mg/L. At the same time, the effect of hydroxyl radicals on the photosynthesis pigments of phytoplankton was done. The results indicate that the contents of chlorophyl-a, chlorophyl-b, chlorophyl-c and carotenoid are decreased to 35 ~ 64% within 8.0 s further to the lowest limit of test after 5 min. When dissolved OH· ratio concentration is 0.68 mg/L, the attenuation efficiencies of photosynthesis pigment are 100%. Therefore the invasive marine species can be killed in the process of the inputting and discharge ship’s ballast water.

The method of ionization discharge has a key action on the process of the ionization and decomposition of O2molecule as well as the re-decomposition of O3molecule. In this paper, an ozone generation of miniaturization which was fabricated by stacking discharge modules with rectangle is introduced, only volume of 23.0×53.0×42.0 cm3for ozone production capacity of 1 kg/hr. In addition, the ozone concentration and its production efficiency are significantly improved in comparison with a conventional ozone generator, which have the highest ozone concentration of 308 g/Nm3and the production efficiency of 118 g/kWh at ozone concentration of 200 g/Nm3.

A miniaturization equipment for 1.0~3.0m3/h with the dimension of 0.6 m (Long) × 0.8 m (Wide) × 1.5m (High) is introduced, which consists of high concentration ozone generator, Mazzi Injector, and gas/liquid dissolving tank. The experimental results indicate that the mass transfer efficiency and dissolved ozone efficiency increase with the increase of ozone gas concentration (CG), system pressure and contact time and decrease with the decreasing of gas/liquid ratio (Vg/Vl) and solution temperature. With this dissolved system, the mass transfer efficiency of ozone was 98.8% in the dissolved process only 1.0m long pipeline or 1.0 s dissolved time and the dissolved efficiency was 75%. The dissolved ozone concentration was in the range of 4.4 ~ 10.0 mg/L for 2.0 m3/h.

Under very simple conditions, we prove the existence of one positive and one negative solution of an asymptotically linear elliptic boundary value problem. Even for the resonant case at infinity, we do not need to assume any more conditions to ensure the boundness of the (PS) sequence of the corresponding functional. Moreover, the proof is very simple.

In this paper, we use Fucik spectrum, ordinary differential equation theory of Banach spaces to study semilinear elliptic boundary value problems with jumping nonlinearities at zero or infinity, especially with resonance at infinity, and obtain new results on the existence of multiple solutions and sign-changing solutions with a weakening of the P.S. condition. In one case we get up to seven nontrivial solutions. The techniques have independent interest.

In this work, dielectric barrier discharge (DBD), a cold plasma phenomenon, was applied for CO2decomposition. To enhance CO2decomposition, we used a frosted dielectric quartz tube on which CeO2was coated. Significantly increased CO2conversion was thus achieved. The CO2conversion reaches 23.3% over the CeO2-enhanced frosted dielectric barrier discharge (FDBD) at 10 mL/min and a discharge power of 14.5 W, whereas it is only 16.3% over the uncoated FDBD at the same conditions. The highest energy efficiency reaches 8.0% at 50 mL/min, with which the energy efficiencies over the uncoated FDBD and the unfrosted quartz tube-based DBD are 6.0 and 5.4%, respectively. The increased CO2conversion with higher energy efficiency is caused by the improved microdischarge performance of the CeO2-enhanced FDBD, with an advantage of easy loading and convenient removal of the CeO2-coated quartz over the traditional DBD packed with CeO2fine particles.

ABSTRACTThis paper presents a technique for the complete, simultaneous decomposition of CO2, SO2, and NOx, as well as the simultaneous removal of fly ash by ultra-high voltage pulse activation. Ultra-high voltage narrow pulse is used to make the gases in the reactor become active molecules, which are then dissociated into nonpoisonous gas molecules and solid particles under the control of a directional reaction model. By using a sufficient charge and a strong electric field, the fly ash can be removed. It becomes the carrier of C and S, and its efficiency is 99.5%. Owing to the action of catalyst B (using Ni as the mother's body), the activation energy of CO2, SO2, and NOxgases is reduced in great magnitude, and their removal efficiency can reach 75~90% at normal pressure and 180 °C.

By reducing the noise component induced by the amplitude-to-phase conversion, a broadband phase-noise suppression of a 20.5 GHz photonic microwave, generated from an optical heterodyne of a dual-wavelength single-frequency fiber laser (DW-SFFL) is experimentally demonstrated. This is done by suppressing the intensity noise of the DW-SFFL through optoelectronic feedback, the microwave shows phase-noise suppression around the frequency range 100 Hz to 100 kHz. The phase-noise suppression of 6.1 dB at 1 kHz offset frequency and a linewidth of 2.15 kHz are obtained from this microwave system. The successful improvement indicates the feasibility of our strategy in obtaining a low phase-noise microwave.

We study the existence of positive solutions to the following Kirchhoff type equation with vanishing potential and general nonlinearity: -(ε2a+εb∫R3|∇v|2)Δv+V(x)v=f(v),x∈R3,v>0,v∈H1(R3),where ε>0is a small parameter, a,b>0are constants and the potential Vcan vanish, i.e., the zero set of V, Z:={x∈R3|V(x)=0}is non-empty. In our case, the method of Nehari manifold does not work any more. We first make a truncation of the nonlinearity and prove the existence of solutions for the equation with truncated nonlinearity, then by elliptic estimates, we prove that the solution of truncated equation is just the solution of our original problem for sufficiently small ε>0.